Automatic furnace



L. GARRISON.

AUTOMATIC FURNACE.

APPLICATION FILED NOV. H1919.

l A$Q9 1 o Patented J 11113 2Q, 1922.

2 SHEETSSHEET I.

my 1 70% /4/2 13 J0 INVZJVTOR,

L. GARRISONI Q AUTOMATIC FURNACE. APPLICATION FILED NOV. I. 1919 llfi fl figl I l Patented June 2%, 1922.

I 2 SHEETS-SHEET Z.

INVENTOR I 47% 5m ATTORNEY Application file-d 7'0 all whom may concern:

lie it known that i "urn Grnnnrsor-T, United States, residing at in the county or Salt inane bituminous coal. its chief application is in.

residences, but it, may be adapted to larger buildings.

lln the accompanying drawings, reference numerals. designate the same parts in all cases. I

Fig. 1 is a plan of the whole apparatus. lit shows the electrical circuits, damper corrnections, and method of delivery oil the fuel to the furnace. Elie automatic furnace control shown is that covered by my copending application, Serial No. 335,147, filed Nov. 1, 1919'. f Fig. 2 and Fig. 3 are respectively side and front elevations of the ratchet pulley;

Figures 4 and 5 are respectively a side elevation and front elevation of the safety device.

Figures 6 and 7 are respectively side and front elevations of the s itch drum controllingthe mechanical fee Figure 8 is a side elevation of the contact disc which switches the thermostat circuit from one terminal of the thermostatto the other. I

Fig. 9 is an enlarged portion of the feed device.

Fig. 10 is a right elevation of the automatic control.

Fig. 11 and Fig. 12 are, respectively, a right elevation and plan, partly in section, showing themethod of placing the chute which conveys the fuel into the furnace.

In the drawings as shown, the furnace is operating, coal is being fed to it, the damper is open and the check draft is closed.

Under the conditions shown in the drawings, the temperature at the thermostat 1,

perature continues until, at. a predetermined upper limit, the leaf 2 touches contact 3. lln

the drawings, the thermostat is shown for purposes of illustration. as being of ordinary lei-metallic type, the leaf of wh bends one way or the other as the temps ture increases or decreases. V l hen made between leaf 2 and contact 3, the low voltage circuit energized by the bell transformer a is completed trom'the terminal. of the transformer, 55, through conductor 6, leaf 2, contact 3, conductor 7, contact spring 8, the metal of contact disc 9, shaft 10, to the base 11. From this it passes through spring 12, arm 13, spring 14, conductor 15, coil 16, conductor 17, back to transformer at terminal 18. The current supplied to the circuit'just outlined by the bell transformer energizes the electro-magnet it which attracts armature 19 placed on one end of the lever 20. Armature 19 moves up, pulling down and closing the spring leaf switch 21.

The high voltage, or motive circuit, is com pleted by the closing of switch 21. Current then flows from supply 'main 22 through terminal 23, conductor 2d, switch terminal 25, switch 21, switch terminal 23, conductor 27, coil 28, conductor 29, terminal 30, l'use 31, terminal 32, conductor 33, terminal 3 and back to the source of supply by main 35. The passage of current through the motive circuit actuates the electromagnet 28 whichpulls down plunger 36. Plunger 36 is connected to spring 37 by cable 38 which runs over ratchet pulley 39 and is secured thereto to prevent slipping by the screw l0. The

construction of ratchet pulley 39 is shown This pulley is rotated freely by the action of more in detail in Figures 2 and 3.

spring 37 but if rotated by the action of plunger 36, shoulder ll on the pulley engages sliding pin 42 and the crank arm l3 is rotated with the pulley. The travel of the plunger 36 is so limited by the stop at and the metal piece 45 that the pulley and crank rotate only one half revolution, of slightly in excess thereof, when actuated by plunger 36. This closes the damper as and opens the check draft 17 which are connected by cables 48 and 49, respectively", to sleeve 50. Sleeve 50 rotates freely on stud 51, set in crank 43. The shaft 10 runs in suitable bearings 53 and to it are rigidly secured the crank 43-, contact disc 9, and drum 54. When crank .43. is rotated by the motion of, plunger 36 acting on pulley 39, disc 9 and drum 54 are both rotated one half revolution. By the rotation of disc 9 one half revolution ice the insulation 55, shown more fully in Figure 8 is brought into contact with spring 8, thus breaking the low voltage circuit; also spring 70 is brought into contact with the metal of disc 9 prepagatory to the next operation. .At the same time spring 8 drops behind the shoulder in the insulation, thus preventing a backward motion of the disc 10 wit-h a consequent remaking of the low volt age circuit. A too great forward rotation of the crank is prevented by leading away the chains to the dam er and check draft in proper directions. hen the low voltage circuit is broken by contact of spring 8 with insulation 55, armature 19 1s released and lever 20 forced back to its original position, partly by the. weight of the armature and partly by the spring leaf 21. 20 This breaks the motive circuit at switch 21 and releases plunger 36 which; is pulled back to the position shown in the drawings by spring 37. The crank is not, however, rotated backwards,'being held by spring 25 8 which is in position behind the shoulder in insulation 55. The rotation of the ratchet pulley backwards causes pin 42 to travel up the incline 56 and drop over the 'second shoulder 41 ready for the next half revolution. Pin 42 is held to the face of pulley 39 by the pressure of spring 57. The combined action of pulley 39 and pin 42 is similar to that of a ratchet. The

. function of spring 12, arm 13, and spring 14, Figures 4 and 5, is that of a safety device. Without this, if for any reason pin 42 should fail to engage shoulder 41 and rotate the crank 43, the; low voltage circuit would not be broken and the plunger 36 40 would be permanently attracted. To pre vent this, the pin 58 is provided, which at the end of the half revolution of pulley 39 caused by the action of the plunger, irrespective ofthe breaking of the low voltage circuit at contact disc 9, strikes arm 13 and breaks its contact with spring 12. This breaks the low voltage circuit with theconsequent release of plunger 36. At the termination of the reverse half revolution of the pulley 39 the pin 59 strikes arm 13 and remakes the connection. If the circuit is not then broken at disc 9 the low voltage current' again immediately actuates magnet 16, closesswitch 21 and pulley 39, is again rotated. This is repeated until pin 42 engages shoulder 41 and the shaft is rotated, breaking the contact at disc 91 The travel of arm 13 is restricted by stop 60. In the event the damper or check draft 60 become caught and the rotation of shaft 10 is prevented, the coil 28 is protected by fuse 31. f

As shown in the drawings, the current which drives the motor of the feed apparatus leaves supply main.22 and traverses conductor 61, motor 62, conductor 63,

contact spring 64, segment 65, contact spring 66, conductor 67, terminal 32, conshow the construction of drum 54. This drum is composed of insulating material which carries the metal segment 65. The action heretofore described whereby crank 43 is rotated one half revolution, thus closing damper 46 and opening check draft 47, also rotates drum 54 one half revolution and breaks contact of the segment 65 with springs 64 and 66; this stops the motor 62 and coal ceases to be fed to the furnace.

In the event a water motor, loose pulley, or other device is. used to drive the mechanical feed, a suitable mechanical device can be substituted for drum 54.

Under the conditions following the action above described, the temperature at the thermostat is decreasing. When it has fallen to the lower limitfor which the thermostat is set, leaf-2 touches contact 68. The low voltage circuit is then once more completed and current flows from terminal 5 of transformer 4 through conductor 6, leaf 2, contact 68, conductor 69, contact spring 70, disc 9, shaft 10, and thence follows the path previously described through coil 16 and back to transformer 4 at terminal 18. The energizing of coil 16 again attracts armature 19, closes switch 21, and magnet 28 is energized. The consequent attraction of plunger 36 rotates pulley 39, crank 43, and shaft 10 one half revolution in the manner heretofore described, thus opening damper 46 ,and closing check draft 47. Atthe same time drum 54 is rotated one half revolution which brings segment 65 in contact with springs 64 and 66, thus completing the circuit through motor 62 and the feeding of coal to the furnace is resumed; also disc 9 is rotated one half revolution which brings spring,8 in contact with the metal of the disc preparatory to, the next operation, breaks the existing low voltage circuit by causing the spring 70 to come in contact with and drop behind the shoulder in insulation 55, releases armature 19, breaks the motive circuit at switch 21, and re-' leases plunger 36 which is immediately drawn back to the position shown in the drawings by the action of spring 37.

Fig. 9 shows more in detail the action of the feedapparatus. 71 is a speed changlng pulley driven by motor 62. Pulley 71 runs on a suitable shaft 72 to which is attached thecrank arm 73. Arm 73 carries the mov able pivot 74 which can be moved along the I arm and is secured in place by the screw 75. Pivot 74 drives the connecting rod 76 which in turn drives the rod 77 and the oscillating slide 78. Rod 77 and slide 78 are secured in place by suitable guides 79 and 80, respectively. Coal runs down the chute 81 as more particularly described in my co-pending ap plication heretofore mentioned and is fed to the conveyor 82 by the oscillations of slide 78. li lotor 62 supplies power for driving conreyor 82. it is readily seen that the rate of discharge of the fuel on to the conveyor may regulatedthrough a wide range by moving the pivot 74-. along the arm 78. Conveyor 8% delivers fuel to the chute The construction of the and its disposition relative the is more particularly shown in l1 and 12. Chute 83 is built with a hopper 8a to receive the the conveyor, and the bottom of the chute 85, has inclination not less than the angle of repose of the fuel resting on the material of which the chute is composed. At the lower end of the chute is a curved defleeting plate 86. This is adjustable with relation to the chute and is held in place by the straps 87. The function of the deflecting plate is to distributev the fuel'in a uniform pile and this is accomplished by so adjusting the deflecting plate that some of they fuel passes under it While other portions strike it and rebound to various parts of the grate. I have found that a uniform conical pile can 91 non-magnetic guides to prevent direct 'l9 without the intervention of lever 20 as be obtained in this way. If fuel, such as bituminous slack coal, is fed from a chute on to the ordinary flat grate it accumulates in a conical pile in the center of the grate. Un- Y der these conditions there is only a small area near the circumference of the grate on which the fuel is su'fiiciently thin to give proper combustion. When the automatic control starts the teed apparatus it frequently happens with a fiat grate that the tire existing in this outer ring of thin fuel is choked or extinguished by the fresh fuel with the result that the temperature at the thermostat continues to fall instead of rising as it would if'the fire was active. The automatic control, therefore, fails to operate and stop the feed. Even when the fire does burn, owing to the small area of useful grate surface included in this outer ring, the fire is so sluggish as to produce very poor regulation and may not attain sufficient volume to cause the automatic control to again operate after it has started the feed. To obviate thls conv dition and produce such a fuel bed as will contact between plunger 36 and the parts of magnetic circuit 92 and 98. 45 is a projection of the magnetic circuit M) which is secured the spring 37. 9d, 95, 98, d7, 98 are insulating supports for the various con tact springs and terminals of the electrical circuits. 99 and 100 are conductors from terminals 23 and ids supplying the primary of the bell transformer l. I

The apparatus is'described as using alternating current such'as is usually obtained from lighting circuits but it will operate equally as well if a battery is substituted for the bell transformer and either alternating or direct'cu'rrent is used in the motive circuit. lf direct current is used in magnet 16, switch 21 may be attached to armature the function of the latter is to eliminate the chattering due to alternating current.

The elimination of manual control by the use of the automatic feature and application of the uniform and adjustable feed, combined with the conical grate, render the rate of combustion very uniform, and enable me to adjust the delivery of fuel to the rate best adapted for proper combustion. ll1e apparatus therefore causes a considerable portion of the gas to be consumed which would be driven off and wasted by any method whichv delivers the fuel in quantities, either by hand or by machinery, and the result is a considerable economy and reduction in smoke.

Y It is understood that the apparatus as shown is in the form adapted to the conditions usually found in connection with furnaces already installed, and to which my inven- 1149 tion may be attached, but in the case ofnew furnaces constructed for use with my apparatus, or of some old furnaces, it may be advisable to replace the feed apparatus witha different type of feed, to discard the conveyor 82 and feed directlyinto the chute. 83; or perhaps to discard both conveyor and chute and feed the fuel directly its into the 'firebox. To the extent of the exlar in shape to the pile of fuel and produces.

a uniform fire over the whole grate surface,

withthe result that the fire is immediately responsive to the addition of fresh fuel and the increase in temperature necessary to cause the automatic control to close the draft and stop the feed takes place as rapidly as the rate of fuel delivery will permit. 'Chute captions stated the feed apparatus, as such, 12% the conveyor 82, and the chute 83 are not claimed as integral parts of my invention.

What I claim as my invention is:

1.,The combination, with a furnace, of a conical grate therein, a mechanical feed for the delivery of fuel thereto, a thermostat operated. by the temperature variations of the air heated'by'the furnace, and an electrically operated device controlled by said thermostat for opening and closing the 3 drafts of said furnace and controlling the operation of the mechanical fuel feed, substantially as described.

2. The combination, with a furnace, of a conical grate therein, a mechanical feed for the delivery of fuel to said furnace, a chute for receiving the fuel from the mechanical feed and distributing it in a conical pile upon the grate, a thermostat operated by the temperature variations of the air heated by the furnace, and an electrically operated device controlled by said thermostat for opening and closing the drafts of the furnace and controlling the operation of the mechanical fuel feed, substantially as described.

3. The combination of: a furnace a conical grate therein; a mechanical feed for the delivery of fuel to said furnace; a chute receiving the fuel from the mechanical feed and delivering itto the furnace; a thermostat operated by the temperature variations of the air heated by the furnace; and an electrically operated device, controlled bythe thermostat, for opening the draft and closing the check. draft of the furnace and starting the operation of the mechanical fuel feed at a predetermined lower limit of temperature of said air, and for closing the 

